Hydraulic circuit with flow divider



March 25, 1958 Filed Jan. 17, 1956 J. F. ZISKAL ETAL- HYDRAULIC CIRCUITWITH FLOW DIVIDER 4 Sheets-Sheet 1 INVENTORS.

March 25, 1958 J. F. ZISKAL ETAL HYDRAULIC CIRCUIT WITH FLOW DIVIDER 4Sheets-Sheet 2 Filed Jan. 17, 1956 30 28 37 1 23 424 2.5 47 34 vINVENTORS. 26 H flag 0A a 40 4.? feyeyze %224(e March 25, 1958 J. F.ZISKAL. ETAL 2,827,768

HYDRAULIC CIRCUIT WITH FLOW DIVIDER Filed Jan. 17, 1956 4 Sheets-Sheet sIN VEN TORS.

104 105 J wf flysaz z @226 f al age Filed Jan. 17, 1956 March 25, 1958J. F. ZISKAL ETAL 2,827,758

HYDRAULIC cmcurr WITH FLOW DIVIDER 4 Sheets-Sheet 4 62 IN VEN TORS-United States Patent *Ofi ice 2,827,768 P atented Mar. 25, 1958HYDRAULIC CIRCUIT WITH FLow urvmnn Joseph F. Zishal, Broohfield, andEugene F. Virtue, Tinley Park, 51]., assignors to InternationalHarvester Company, a corporation of New Jersey Application January 17,1956,, Serial No. 55?,45

6 Claims. (Cl. oil-97) This invention relates to a fluid flow dividingmechanism. More in particular this invention relates to a mechanism fordividing the flow of a source of fluid under pressure whereby the flowof fluid delivered to one outlet thereof is regulated or metered andalternate means for discharging excess fluid from said source at lowpressure to another outlet thereof or making available said excess fluidat high pressure fora secondary purpose.

As an example of the utility of such a device attention is directed tothe fact that wheel type tractors are now manufactured which employhydraulic power steering mechanisms of the kind which requires thedelivery of fluid at a substantially constant pressure during theoperation thereof. 'For this purpose it is the practice to provide aseparate hydraulic pump on the tractor to provide fluid undersubstantially constant-pressure when the power steering motor is inoperation and by-passing the fluid when the power steering motor ismotionless or at rest. Frequently the same type of tractors are providedwith hydraulic lift mechanisms for elevating associated implements intransport position. For example a tractor may be connected to a plowwhereby the plow may be raised hydraulically to facilitatetransportation thereof from one place to another. Thus a single tractormay have two or more independent hydraulic systems requiring anindividual pump for each system.

In order to'reduce costs the primary purpose of this invention is toprovide an hydraulic circuit or system having but a single hydraulicpump which system will power an hydraulic steering motor of the typedescribed and, in addition thereto, one or more secondary hydraulicmotors such as hydraulic rams.

Another object of this invention is to provide an hydraulic flow dividervalve arrangement adapted to deliver through one outlet thereof fluid ata metered rate and at substantially constant pressure and a secondoutlet adapted to bypass excess fluid under pressure for dischargethereof or delivery to a second hydraulic motor and control valvetherefor.

These and other desirable objects inherent in and encompassed by theinvention will be more readily understood h'om the ensuing description,the appended claims and the annexed drawings wherein:

Figure 1 is an hydraulic system or circuit included in this invention,in schematic form, diagrammatically illustrating the flow of fluid to apower steering motor at rest and a second fluid motor also at rest.

Figure 2 is similar to Figure 1 except that it illustrates the flow offluid when the second fluid motor is in operation.

Figure 3 illustrates the construction, in section, of the flow controlvalve or flow dividing valve of this invention.

Figure 4 illustrates a form of the invention in which the hydrauliccircuit is modified slightly over that shown in Figure 1.

Figure 5 is similar to that of Figure 4 except that it 2 illustratestheflowof fluid when the second fluid motor is in operation.

Referring to the drawings illustrating a preferred embodiment of thisinvention, generally indicated at 10, con sists of afirst control valve11 and a second control valve 12, a servo-motor assembly 13 including afirst fluid motor 67, a second fluid motor 14, a fluid pump 15 which mayinclude a reservoir 16, and a fluid flow dividing mechanism 17. Thefluid flow dividing mechanism 17 comprises a fluid flow regulating valve18 operably controlled by a ram 19, a fluid flow dividing valve 20, andmay optionally include a'relief valve 51. The aforementioned elementsare interconnected together suitably by various conduits, tubes or fluidpassages'to form a fluid circuit or system as hereinafter described.

A novel and ingenious feature of this invention is the inclusion of thefluid-flow dividing valve 20. The primary function of this valve 20 isto meter a first portion of fluid flow entering the inlet port 21thereof for delivery to a-flrst outlet port 22 at a substantiallyconstant rate of fluid flow. The excess portion of fluid 'flow enteringthe inlet port 21 over and above that delivered to the first outlet port22 is directed to a second outlet port 23. The construction of the fluidflow dividing valve 20 will now be described.

Referring to Figure 3 the fluid flow dividing valve 20 consists of ahousing 24 having a large longitudinalhole 25 therethrough. A rear headmember 26 is positioned at one end of the hole 25 and held rigidly tothe housing 24 by any one of the various commonly known methods such asa pressed fit or by providing an enlargement .27 of the hole 25 formingan abutting shoulder 28 for the head member 26 for preventing inwardmovement thereof. Outward movement of the head member 26 may berestrained by employing a snap ring 29 suitably received in an annulargroove 30 in the housing 24 and a corresponding annular groove 31 in thehead member 26. A fluid seal 32 may be disposed circumferentially aboutthe head member 26 to prevent fluid leakage therethrough. A front headmember 33 is rigidly mounted in the opposite end of the hole 25similarly to that described for the rear head member 26.

The inner portion of the front head member 33 is provided with a seatelement 34 adapted to anchor one end of a captive helical spring 35.

Within the housing 24 is disposed slidably in the hole 25 a reciprocablevalve member 36. The member 36 is provided with a large bore 37 adaptedto accommodate the other end of the spring 35, said bore extendingadjacent the rear end of the member 36 to form a seat 33 for the captivespring 35. A small bore or first metering passage 39 is provided in oneend portion 41 of the member 36 to communicate for fluid flow the largebore 37 with a chamber 48 formed by the housing 24, head member 26 andone end portion 41 of the member 36. Thus it will be seen that thereciprocable valve member 36 is urged rearwardly by the spring 35.

Adjacent the rearward end of the reciprocable valve member 36 is a largeor Wide circumferential groove 42 of suflicient axial length to effectregistration with the inlet port 21 for fluid flow irrespective of axialmovement of the valve member 36. The circumferential groove 42 is'communicatively connected for fluid flow to the chamber 46 by means ofone or more channels 43 longitudinally disposed in the periphery of thevalve member 36 as best shown in Figure 3. Thus the inlet port 21 isalways communicatively connected for fluid flow to the large bore 37 ofthe valve member 36 through the channel 43, chamber 40 and small bore orfirst metering passage 39. The second outlet port 23 is positioned toregister with land 44 when the reciprocable valve member is in theposition shown in Figure 3 thus preventing fluid flow from the inletport 21 to the second outlet port 23. However, when the fluid pressureat the inlet port;21 reaches a predetermined limit set by thecompressive characteristics of the spring 35, the fluid pressure ,actingon the annular surface '45 formed by the groove .42 and land 44 and therearward end of the member 36 adjacent the chamber 40 causes forwardmovement of the valve member 36'which movement permits flow of fluidfrom the groove 42 to the second outlet port 23. From this it can bebeen that the valvingby the relation of the land 44 wtih the housing 24throttles the flow of fluid from'the groove 42'to the second outlet port23 :because the spring 35 urges the valves member 36 rearwardly and theforward motion of the'member 36 must beca used by fluidpressurein thegroove 42 acting on V .the annular surface 45 and the rear end of themember 36 to compressthe spring 1 It: will be noted in Figure 3 that theforward end annular face 47 of the reciprocable valve member 36 ispositioned to register with the first outlet port 22 to form a secondfluidmetering passage 48 which communicates for fluid flow the bore 37with the first outlet port 22. However, asf'the valve member 36 movesforwardly fluid flow through the'second fluid metering passage 48 isprogressively restricted or throttled and becomes completely closed whenthe valve member 36 reaches its extreme forward limit. The forwardmovement of the valve member 36 is limited by the annular portion 49 ofthe seat 34 serving as a stop means when the annular face 47 is inabutting relation thereto.

Adjacent and rearwardly of the annular face 47 of the 'valve member 36is a small annular groove 46 positioned to communicatively register withthe first outlet port 22 irrespective of the axial position or movementof the valve member 36. 'A u'ansversely disposed small port or snubbingport 50 in the valve member 36 is provided to connect communicativelyfor fluid flow the bore 37 with the small annular groove 46. Thus thesnubbing port'50 is always in communication with the first outlet port22. through the groove 46. The purpose of the snubbing port 50 is toprevent the stoppage of fluid flow to the first outlet port 22 duringperiods when the system 'is subjected to momentary pressure surges ofsuflicient magnitude to move the member 36 forwardly to its limit thusclosing the second metering passage 48. The

port has in such instances the eifect of snubbing the sudden forwardsurge of the member 36 and allows fluid to enter the first outlet port22 at such times to feed fluid to the servo-motor assembly 13. Also whenthe servomotor assembly 13 is actuated momentarily the port 50 snubs ordampens any chattering tendency of the member 36. 7

From the foregoing it can be seen that when fluid is delivered to theinlet port 21 at low pressure, the entire fluid flow passes from theinlet port 21 to the groove 42, thence through the channel 43 to thechamber 4% thence through the small bore or first metering passage 39 tothe large bore 37 of the valve member 36, thence through both thesnubbing port 50 and associated groove 46 and the second fluid meteringpassage 48 to the first outlet port 22. Under low pressure conditionsnone of the fluid passes to the second outlet port 23 because the land44 is in complete registration with the second outlet port 23; 7

Now as the fluid flow at the inlet port 21 increases the pressuredifferential between the chamber 49 and the opening formed by the largebore 37 also increases due to the restriction of fluid flow through thesmall bore or first fluid metering passage 39. This pressuredifferential when of suflicient high magnitude causes forward movementof the member 36 thereby further compressing the captive spring 35. Theforward movement of the member 36 results in that the second fluidmetering passage 48 is progressively restricted and the fluid isthrottleci 4 V therethrough. From this it can. be seen that as thereciprocable valve member 36 is progresively moved for= wardly themetering of fluid flow to the first outlet port 22 is shifted from thefirst fluid metering passage 39 to the second metering passage 48; Whenthe member 36 moves forwardly to begin throttling fluid flow through Vthe second metering passage 48 a corresponding'backpressure is createdin. the opening formed by the large bore 37 which back-pressure reducesthe pressure dif ferential between the chamber 40 and the opening formedby the large bore 37 as the fluid passes through the fluid restrictioncaused by the first fluid metering passage 39. Thus; the valve member 36moves forwardly thereby throttling fluid through the second'fluid metering passage 48 to a point where the above described back-pressureaugmented by the urging of the spring 35 balances the pressure of fluidin the groove 42 and chamber 49. As the fluid flow continues to increaseat the inlet port 21 the. second fluid metering passage 48 isprogressively restricted and the fluid is throttled correspondinglytherethrough. The forward movement of the'valve member 36 causes thegroove 42 to register with the second outlet port23 thereby by-passingthe excess fluid therethrough. 'Now in the case of sudden pressuresurges when the fluid pressure at the inlet port 21 rises toapredetermined pressure limit, the valve member 36 will have momentarilyat least reached its extreme forward position whereby the second fluidmetering passage is completely closed and the only fluid flow to thefirst outlet port 22 is through the snubbing port 50 and associatedannular groove 46. Thus it may be seen that fluid flow to the firstoutlet port 22 is maintained at substantially a constant rate orpressure and the excess fluid discharged through the second outlet port23. e

The relief valve 51 of Figures 1 and 2 may be said to be optionallyprovided unless the capacity of the pump 15 appreciably exceds the fluiddelivery necessary to move the reciprocable valve member 36 of thedividing valve 2t) to its extreme forward position as previouslydescribed. The relief valve 51 may be of the ordinary known check valvedesign adapted to permit flow of fluid therethrough when the pressureexceeds' a predetermined value. 7 The relief valve 51 in this instancemay be comprised of an inlet port 52 and an outlet port '53, a slidableplunger 54 urged in seating relation with a seat-55 by a captive spring56. The fluid under pressure entering the inlet port 52 of the valve 51acts upwardly to urge upward movement of the plunger 54 against theforce of the spring 56to unseat the plunger 54 thereby allowing thefluid to escape to the outlet port 53 thereof in a commonly knownmanner. From this it is evident that the compressive characteristics ofthe spring 56 determine the fluid pressure at the inlet port 52necessary to actuate movement of the plunger 54 to open therrelief valve51 allowing the'fluid to escape therethrough to the outlet port 53thereof. An ordinary well known ball-type check valve would functionsimilarly. a .The fluid pressure regulating valve 18' including thecontrol ram 19 therefor comprises essentially a ball valve wherein theball 57 -is normally urgedin seating relation with a seat '58 similar tothe known balltype check valve. The regulating valve 18'isprovidediiwith an inlet port 59 andan outlet port 60. jAs will be notedfrom Figure2 the ball 57 is urged into seating; relation with the seat58 by the spring 61. Thus it can be "seen that normally the regulatingvalve 18 is closed as, the ball 57 is kept seated by fluid underpressure at the inlet port 59 thereof actingon'the ball coupled with theurg ing of thespring61. It is also evident that in order to unseat theball 57 a downward force must be applied to 7 the ball 57 of suflicientmagnitude to overcomethe .fluid pressure entering the inlet port 59 andacting upwardly on the ball '57 as Well as the upward urging of thespring 61 One way for applying the necessary force to unseat the ball'57 of the regulating valve 18 is by means of a small single actingfluid rain 19. The ram 1'9 may be of the ordinary known type having apiston 62 with a work member "63 rigidly connected thereto.

The ram 19 is provided with a port 64 which is adapted to conduct fluidunder pressure into the enclosure 65 for acting on the piston 62 to urgethe work member 63 in a downward direction. The lower end 66 of the workmember 63 abuts or engages the ball 57 and when sufiicient fluidpressure enters the enclosure 65 the ball 57 is forced downward tounseat thereby opening the regulating valve 18 to discharge fluid fromthe inlet port 59 thereof to the outlet port 60 thereof. When the fluidpressure is reduced in the enclosure 65 the spring 61 urges the piston62 upwardly to reseat the ball 57 to close the regulating valve 18 andthe fluid in the enclosure 65 is forced out the port 64. Thus bycontrolling the fluid pressure at the port 64 of the ram 19 the flow offluid from the inlet port 59 to the outlet port 6% of the regulatingvalve 18 may be throttled from a closed position to a fully openposition.

The fluid pump 15 and associated reservoir 16 may be of any of the wellknown types and for purposes herein maybe described as any source offluid under pressure. For example an ordinary gear pump provided on manywell known tractors is quite satisfactory for use in the fluid circuitof this invention.

As previously mentioned the fluid circuit of this invention includes aservo-motor assembly 13 and 'a second fluid motor 14. The servo-motorassembly 13 is of the type wherein fluid is by-passed therethrough whenthe servo-motor assembly 13 is motionless. An example of such aservo-motor assembly 13 is a power steering device. The servo-motorassembly 13, as schematically illustrated in Figures 1 and 2, maycomprise a two-way acting fluid cylinder 6'] (schematically indicated)associated'with theground engaging front wheels of a tractor or othervehicle. The front Wheels of the vehicle (not shown) are associated withcore element 68 of a steervalve 69. A manually operable steering wheel(not shown) is associated with a valve sleeve element 70. A pairof pipes71 and 72, one for conducting fluid under pressure to the cylinder'67While the other conducts discharge fluid from the cylinder 67 in acommonly known manner, are connected to a pair of ports 73 and 74respectively. The illustration shown in Figure 1 shows the steering oroperating valve 69 'ina neutral or motionless position. The fluid underpressure entering the inlet port 75 of the steering valve 69 in theneutral position as shown is conducted to a discharge port 76 as"indicated by the arrows in Figures land 2 of the steering valve 69.When the valve sleeve element 70 is manually rotated in a clockwisedirection the fluid entering the inlet port 75 is permitted to how onlyinto the port 73 and pipe 71 to the cylinder 67 thus energizing thecylinder 67 in one direction. The discharge fluid from the cylinder 67flows through'the pipe72 and port 74 tothe discharge port 76. Since thecylinder 67 is now energized in one direction the ground engaging wheelsmovecorrespondingly to'turn the vehicle and the core element 68associated therewith moves in a clockwise direction'nntil the coreelement 68 reestablishes a neutral position with respect to the valvesleeve element 70 in a commonly known manner. A counterclockwisemovement of the sleeve member 76 causes 'the reverse movement of thecylinder 67 in a similar manner to that just described. In other wordsthe cylinder 67 always tends to urge the steering mechanism in adirection to reestablish the valve 69 in a neutral condition therebypermitting the fluid entering the inlet port 75 *to by-pass freely tothe dis chargeport 76 while the servo-motor assembly 13 is motionless.

The second fluid motor '14 may be of any of the well known types and forpurposes of this invention an ordinary two-way acting mm was selected.The second fluid motor comprises the usual housing having a movablepiston 77 and associated connecting rod 78. g The ports 7 9 and '80, onebeing connected to each end of the motor 14, serve to introduce fluidfor energizing the motor 14 in one direction While discharging fluidthrough the other in a commonly known manner.

The fluid circuit of this invention also includes a first control valve11 and a second control valve 12. The first control valve 11 may consistof an ordinary well known shut-oil valve as its purpose is to controlthe ram 19 of the regulating valve 18. The second control valve 12 mayalso consist of any well known type of valve used for controlling theadmission of fluid under pressure to a fluid motor and conducting theexhaust fluid therefrom. However, for simplicity, the first and secondcontrol valves 11 and 12 may conveniently be combined into a singlemechanism because both said valves are usually operated simultaneously.Referring to the drawings the combination first and second control valveunits 11 and 12 comprises the usual housing having a slidable plunger 81movable axially as shown in Figures 1 and 2. For manually controllingthe axial movement of the plunger 3'1 a lever 82 is "mounted on thecontrol 'valve housing pivotally connected for rocking motion at 83. Arock arm 84 is rigidly connected to the lever 82, the extendin'g "endportion being pivotally connected to the .plunger $31 at 85. Thus it canbe seen that rocking of the lever 82. will cause the plunger 81 to moveaxially with respect to its housing.

The plunger 81 is provided with annular grooves .86, 37, '83 and 89 asshown in Figure 1. Adjacent these annular grooves 86, 87, 88 and '89 arelands "90, 91 and 92. Positioned in the housing for registration withthe grooves'86, 87, 38 and '89and thel'ands 90, 91a'nd92 are ports 93,94, 95, 96, '97 and 98. Referring to 'theillustration in Figure 1 it maybe seen that both control valves 11 and 12 are in neutral or closedposition. The port 95 is the inlet port for receiving fluid underpressure. The port 95 'is in registration with the groove 88 whichgroove is not in registration with'any other port a'ndhe'n'c'e no fluidflows through the "port 95 when the valves '11 and 1-2 are in theneutral position. The port '94 communicates withone side of the secondfluid motor 14 by a tube 99. The land 91 is in registration with theport 94 and hence no fluid flows through the tube '99. The port 96communicates with the other side of the second fluid motor 14 by anothertube "109. The land 92 is in registration with the port 96 and hence nofluid "flows through the tube 100. Thus in the neutral position of thecontrol valves 11 and 12 the second fluid motor 14 is maintained underfluid lock. The port 93 is an inlet port of the first control valve 11and since it is in registration with the land no fluid flows through theport 93. Ports 97 and 98 are discharge .ports but since the controlvalves 11 and 12 are both in neutral, Figure 1, no fluid flowstherethrough.

Now referring to Figure 2 it will be seen that the lever 82 is moved inthe-rightward direction causing the plunger 31 to move upwardly from theneutral positionillustrated in Figure l. The groove-87 is now inregistration with the discharge port 97 and the inlet port 93 of thefirst control valve 11 thus permittingfluid'flow from theinlet port 93through the groove '87 to the dischargeport-97. At the same time thegroove 88 of the second control valve 12 is in registration with thefluid pressure inlet port 95 and the port 94 thus admitting fluid under.pressure to one side of the second fluid motor 14 through the tube 99and motor port 79. Simultaneously the groove 39 is in registration withthe port 96 and the discharge port 98 thereby permitting'the exhaust offluid from the other end of the second fluid motor 14'through the -motorport 80, tube 100, port 96,groove'89to the dischargeport 98. Thus inthisrightward'positio'n of the c'ontrol valves 11 and 12 thesecondfluidmotor is energized and provision'made for exhausting fluid from theother side of the motor 14 in a commonly known manner.

Althoughnot shown in the drawings it will be appreciated by one skilledin the art that the lever 82 may be moved in the leftward direction fromthe neutral position shown in Figure 1 which will cause the plunger 81to move downwardly from the neutral position. The groove 86 thenregisters with the discharge port 97 and the inlet port 93 of the firstcontrol valve 11 thus permitting fluid flow from the inlet port 93through the groove 86 to the discharge port 97. At thesame time thegroove 88 of the second control valve 12 is in registration with thefluid pressureinlet port 95 and the port 96 thus'admitting fluid underpressure to' the other side of the second fluid motor through the tube100 and themotor port 80. Simultaneously the groove 87 is inregistrationwith the port 94 and the discharge port 97 therebypermitting the exhaust of fluid from the one end of the second fluidmotor 14 through the motor port 79, tube 99, port 94, groove 87.to thedischarge port 97. Thus in this leftward position of the lever 82 of thecontrol valves 11 and 12 the second fluid motor is energized in theopposite direction from that shown in Figure 2 and provision made forexhausting fluid from the one side of the motor 14 in a commonly knownmanner.

Each of the various elements or mechanisms have been described above andthe various fluid conducting conduits interconnecting these elements toform the hydraulic circuit of this invention will now be described.

A first fluid pressure conduit 101 is communicatively connected forfluid flow to the fluid outlet means 102 of the pump 15 to the inletport 95 of the second control valve 12 as shown in Figures 1 and 2. Thefirst pressure conduit 101 is also communicatively connected to theinlet port 52 of the relief valve 51 and the inlet port 21 of the fluidflow dividing valve 20. A second pressure conduit 109 is connectedcommunicatively for fluid flow to the first outlet port 22 of thedivider valve and the inlet port 75 of the servo-motor assembly 13. Afirst fluid discharge conduit 103 communicatively connects for fluidflow the fluid inlet means 104 of the pump 15, including the reservoir16 with the discharge port or outlet port 76 of the servo-motor assembly13. The first discharge conduit 103 is also communicatively connected tothe discharge port or outlet port 60 of the fluid pressure regulatingvalve 18, and the discharge or outlet port 53 of the relief valve 51.Further, the first discharge conduit 1193 is communicatively connectedto the port 97 of the first and second'control valves 11 and 12 andthe'port 98 of the'second control valve 12 as shown in Figures 1' and 2.A second discharge conduit 105. communicatively connects for fluid flowthe second discharge port or second outlet port 23 of the fluid flowdividing valve 20 with the inlet port 59 of pressure regulatr ing valve18. A third discharge conduit 1% communicatively connects for fluid flowthe second discharge cond nt-195 with the port 64 of the ram 19associated with the regulatingvalve 13. At this point it will be notedthatith'ethird discharge conduit 11% is provided with a fluid flowrestriction means such as an orifice 1117 for the purpose of reducingthe rate of fluid flow therethrough as will hereinafter be discussed.The orifice 107 may be in the form of a reduced diameter portion of theconduit 1% or may conveniently be an adjustable valve such as acommonly'known needle-type valve. A

, fourth discharge conduit 16S communicatively connects for fluid flowthe port 93 of the first control valve 11 with the third dischargeconduit 106.

In the modified hydraulic circuit of this invention as shown in Figures4 and 5 the only change from that shown in Figures 1 and 2 is that theinlet port 95 of the second control valve 12 is connected to the seconddischarge conduit 105 leading to the second outlet port 23 of the fluidflo'w dividing valve 20 instead of being con be appreciated thatordinary air as a fluid medium may also be used in which case, ofcourse, the first discharge conduit 103 may be eliminated as theatmosphere itself would become a part of the circuit.

Operation In the case where a fluid circuit of this invention is used ina tractor or other vehicle it can be appreciated that the fluid pump 15will be operated at various speeds due to the varying speed of thevehicles engine or power plant and hence the delivery of fluid by thepump 15 to the first pressure conduit 101 fluctuates accordingly. Withthis in mind consider first the operation of the fluid circuit of thisinvention in. accordance with the illustration in Figure l where thefirst and second control valves 11 and 12 are both in neutral or closedposition. Assume first that the pump 15 is operating at low speed andhence the fluid delivery to the first pressure conduit 101 is of a lowmagnitude. It will be seen that since the control valves 11 and 12 areboth closed no fluid from the first pressure conduit 101 will flowthrough the port 'be- 1 cause theannular groove 88 is not inregistration with any other port. Similarly no. fluid flows through thefourth discharge conduit 108 because the land 90 of the plunger 31 is inregistration with the port 93. Also no fluid flows from thefirstpressure conduit 101 through the relief valve 51 because, ofinsuificient pressure to open the valve 51. The entire flow of fluidfrom the. pump '15 is therefore conducted to the inlet port 21 of thedivider valve 20. Since the fluid pressure at the port 21 is of lowmagnitude the spring 35 maintains the reciprocable valve member 36 tothe extreme leftward position thus positioning the land 44 of the member36 in complete registration with the second outlet port 23 andhence nofluid flows into the second discharge conduit 105. 7

The fluid entering the port 21 of the divider valve 20 is directed intothe circumferential groove 42, thence through the channel 43 into thechamber 40, thence through the small bore or first metering passage 39into the large bore 37, thence'through the second fluid metering passage48 and the small or snubbing port 50 and associated groove 46, thencethrough a second pressure conduit 109 into the inlet port 75 of thesteering valve 69 associated with the servo-motor assembly 13 anddischarged through the port 76 into the first discharge conduit 1133which in turn conducts the discharged fluid back to the pump 15 and itsassociated inlet means 104 through the fluid reservoir 16.

Now as the pump 15 increases its delivery of fluid to the first pressureconduit 101 the fluid flow increases at the port 21 of the divider valve20. The increased.

fluid pressure delivered to the divider valve 20 acts on the annularsurface 45 and the rear face of the reciprocable valve member 36 causingthe member 36 to move rightwardly against the urging of the spring 35.The rightward movement of the member 36 is caused by the pressuredifferential between the groove 42 with chamber 4'?! and the openingformed by the bore 37 due to the fluid restriction occasioned by thefirst fluid metering passage 39. The rightward movement of the member 36causes a progressive restriction in the flow of fluid through the secondfluid metering passage 48. At the same time the circumferential groove42 comes into part registrationwith the. second outlet port 23 of thedivider duit 105.. The fluid so entering the conduit from the secondoutlet port 23 of the divider valve 20 is cause'the ball 57 is inabutment withthe seat 58 by the upward urging of the spring 61 'asillustrated in Figure 1.

However, the fluid in the conduit '105 is diverted into the conduit 1%and through the orific'e '107 to the port 64 and enclosure 65 of the ram19 where the fluid acts on the piston 62 thus forcing the piston '62'and"associated work member 63 downwardly. The lower end 66 of the member63abuts the ball 57 of'the regulating valve 18 against the upward urgingof the'sp'ring 61 to unseat the ball '57 from the seat '58 therebyopening the regulating valve 13 as illustrated in Figure 1. The fluid inthe conduit 105 is throttled through 'the regulator valve 18 to thefirst discharge conduit 103. Itwill bes'een that'the regulating valve 18will throttle the fluid therethrough because the activity ofthe ram-19'isd'ependent upon the fluid pressure occurring in the'conduit 106.

From the above it may be appreciated that if the delivery of fluid fromthe pump continues to increase as'may be occasionedby suddenpressuresurges the reciprocable'valve member 36 of the divider valve will reachits extreme rightward position thus closing the second fluid meteringpassage'48 so that the only fluid passing into the conduit 109will'bethrou'g'h the'snubbing port 50 and associated groove 46.

As the fluid delivered by the pump 15 to the conduit 101 furtherincreases, the ball 57 will recede further from thes'eat 58 to permitthe excess fluid flowing throughcond'uit 105 to discharge through theregulator valve 18 to the discharge conduit 103. The further'movem'entof the ball 57 downwardly occurs because the increased pressure in theconduits 105 and 106 actuates the'ram 19 to a greater degree asheretofore discussed. When the fluid delivered by the pump 15 reaches asufliciently high value toop'en the regulating valve 18 t'o its limit,the relief valve 51 should begin to open in throttling relation uponsure conditions which the pump '15 may deliver, the

available fluid delivered to the servo-motor assembly 13 through theconduit 109 is substantially at a constant value and therefore theservo-motorass'embl'y 13 may be operated at any time under substantiallyconstant conditions. I

Suppose now the operator desires to use the second fluid motor '14.Referring to Figure 2 it will be seen that clockwise or rightwardmovement oi the lever 82 causes the plunger 81 to move upwardly. V Thegroove'87 now registers with ports 93 and 97 to permitfluid to how fromthe fourth discharge conduit 108 through, the first control valve 11into the first discharge conduit 103 which conduit leads back to thepump 15. At the same time the groove 88 of the second control valve 12moves into registration with ports 95 and 94 thereby permitting fluidunder pressure from the pump 15: and'first pressure conduit 101 throughthe second control valve 12 and the tube 99 into one side of the secondfluid motor 14. The pressure of the fluid in the motor 14 urges thepiston 77 upwardly and the fluid on the other side of the motor 14 isexhausted through the tube 100 and port 9 6. The groove 89 is now inregistration with ports 96 and 98 thus permitting the'exhaustfluidfromthe motor 14 to pass through the second control 'valve 12 anddischarge into'the first discharge conduit 103 which conduit leads backto the inlet means of the pump 15.

Assuming for the moment that the pump 15 is operating at idling speedand the delivery offluid to the first pressure conduit 1131 is of lowmagnitude such that barely enough pressure is supplied necessary to meetthe requirements of the servo-motor assembly 13 including the steeringvalve 69 therefor. The fluid entering the port 21 of the'divider valve20 would belinsuflicie nt to move the reciprocable'member 36 inarightward'direc- 'tion against the urging of the associated'spring 35.Thus as in the vprevious casethe fluid entering the port 21would'be'directed'throu'gh the dividerfvalve 20 and into '69. Sincethe'discharge of fluid from the 'fifst pressure conduit 101 t'o'thefirst discharge conduit 193 thus described is without any substantialrestriction, no sub stantial fluid pressure re'sults'at'the port of thesecond control valve 12 and hence the second fluid motor would not beenergized. Suppose at this point the operator moves the steering valve69 to actuate the cylinder 67. The'actu'ation of theservo-motor'assembly 13 would restrict the flow through the steeringvalve 69 into the first discharge conduit 103 which restriction causes abackpressure in the conduit 109. Since the pump 15 is operating atidling speed the delivery'of fluid in the conduit 101 would not besuiflcient to move the reciprocablemember 36 in a rightward directionand such low fluid delivery inthe conduit 1G1 is insufiicient toenergize movably the second fluid motor 14 under load, the entirepressure emanating from the pump 15 is expended to move the cylinder 67of the servo-motor assembly 13. Thus under low fluid delivery of thepump 15, the*servomotor assembly 13 has the benefit of the pumps entireoutput as the back-pressure upon the servo-motor assembly 13 is too lowto move the motor 14.

'Now irrespective of whether the servo-motor assembly 13 is in operationor motionless if the output of the pump 15 is momentarily increased suchas a pressure surge, the fluid pressure in the conduit 1G1is'momentarily increased because the reciprocable valve member 36 of thedivider valve 20 will move rightwardly to its limit thus closing thesecond fluid "metering passage '48 and'the only fluid flow to theservo-motor assembly '13 thereafter will be through the snubbing port 50and its associated groove 48.

During the period of the pressure surge when the valve member 36 is atits extreme rightward limit, the pressure in the compartment within bore37 becomes substantially'equal to the pressure in the chamber 40 andgroove 42 thereby exercising no appreciable force to move thevalvemember 36. Therefore spring 35 moves the valve member '36 leftwardto again reestablish the second fluid metering passage 48 in throttlingrelation. From this it can be seen that the port 50 acts tocause asnubbing eflect on the rightward movement of the valve member 36 duringthe said pressure surge.

Meanwhile as the 'reciprocable valve member 36 moves rightwardly thesecond outlet port 23 of the divider valve 20 will progressively comeinto registration withthe circumferential groove 42 therebycommunicating for fluid flow the first pressure conduit 191 with thesecond discharge conduit 105. However, the flow of fluid through theconduit 105 is restricted by the orifice 197 and the fluid which passesthrough the orifice 197 is promptly discharged through the fourthdischarge conduit 108 which is now in communication with the firstdischarge conduit 103 through the first control valve 11 as hereinbeforementioned. Thus no fluid under pressure enters'the port 64 of the ram'19 and therefore the ram 19 is not energized to open the regulatorvalve 18. From this it can be seen that at the higher pump deliveringvalues the only fluid which flows through the port 21 of the dividervalve20 is limited to the amount which escapes throughthe orifice 107and the normal demand required for the servo-motor assembly 13. With thelimited flow of fluid through the port 21 of the divider valve thuslimited 'as above described, the excess fluid delivered'bythe pump 15 tothe conduit 101 is diverted to the port 95 of the second control valve12 and the fluid pressure is conducted through the second control valve1.2 and the tube 99 into the port 79 thus energizing the fir st fluidmotor 14 causing corresponding movement of the piston 77. It should benoted that under conditions illustrated in Figure 2 the regulator valve18 is closed at all times since no fluid pressure is available toactuate the ram 19. Furthermore, as in the previous case if the deliveryof the pump 15 causes a pressure rise in the conduit 101 above apredetermined limit the relief valve 51 opens to throttle a discharge offluid directly into the discharge conduit 103.

' In the modified form of the invention as illustrated in Figures 4 and5 the operation is almost identical with that described for Figures 1and 2. The only difference is that instead of connecting the inlet port95 of the second control valve 12 for operating the second fluid :rnotor14 to the first pressure conduit 101, the inlet port :95 is connected tothe second discharge conduit 105 which provides a distinct advantageover the circuit shown "in Figures 1 and 2.

In the previously described circuit illustrated in Figures 1 and 2, itwill be noted that if the operator engages the second fluid motor'14 byoperating the lever 82 associated with the first and second controlvalves 11 and 12 at a time when the second fluid motor is not loadedvalvef niemberfa first fluid metering passage disposed in one endportion of said valve member for communicatively connecting for fluidflow said bore with said groove, an inlet port disposed in one endportion of said housing, said inlet port being positioned for contlnuousregistration with said groove, 21 source of fluid delivery or under avery light load and the pump 15 is only idling and thus delivering apressure of low magnitude to the conduit 101, the second fluid motor 14would move thus bleeding the fluid from the conduit 101. Under suchconditions this bleeding of fluid from the conduit 101 may have someadverse effect on the fluid delivery to the servo-motor assembly 13through the flow dividing valve 20. Although such conditions areunlikely to occur during normal operation nevertheless the remotepossibility of affecting adversely the operation of the servo-motorassembly 13 may be undesirable. The modification of the circuitillustrated in Figures 4 and 5 overcomes the above described undesirablepossibility because in the modified form of the invention it isnecessary that the pump 15 delivers sufiicient fluid to the conduit 101to move the reciprocable valve member 36 of the divider valve 2%)rightwardly to register the groove 42 with the second outlet port 23 tothrottle fluid into the conduit 105. Since in the modified form of theinvention the operation of the second fluid motor 14 and associatedcontrol valves 11 and 12 is dependent upon fluid discharge into conduit105 through the divider valve 20, it becomes obvious that under allconditions the servomotor assembly 13 will be fully operative providedthat the pump 15 delivers suflicient fluid to meet the minimum demand ofthe servo-motor assembly 13. Thus under no circumstances will the secondfluid motor 14 be operative unless the pump 15 delivers sulficient fluidto the divider valve 20 in excess of the demand required by theservo-motor assembly 13.

From the above it should now be apparent to those skilled in the artthat the servo-motor assembly 13 is provided first with its fluidrequirements under substantially constant conditions from the source offluid delivery while substantially all of the remaining available fluidfrom the said source of fluid delivery is available for operating thesecond fluid motor 14. Of course, it should be understood that aplurality of motors may be substituted for the described second fluidmotor 14 which motors may be connectable' to the fluid circuit of thisinvention by providing a suitable second control valve 12 to operateeach additional motor.

Having thus described an embodiment of the invention, it can now be seenthat the objects of the invention have been fully achieved and it mustbe understood that changes and modifications may be made which do notdepart from thespirit of the invention as disclosed nor from the scopethereof as defined in the appended claims.

What is claimed is: a I

l. A fluid flow dividing valvetcomprising a housing, a reci rocablevalve member mounted within said houscumferential groove disposed on oneend portion of said connected to said inlet port, a first outlet portdisposed adjacent the other end portion of said housing, a second fiuidmetering passage disposed at the other end portion of said valve member,said second fluid metering passage being in registrable position forcommunicatively connecting for fluid flow in throttling relation saidbore with said'first outlet port, a snubbing port disposed in said valvemember adjacent said second fluid metering passage, said snubbing portbeing positioned for continuously communicating for fluid flow said borewith said first outlet port, a second outlet port disposed in saidhousing, said second outlet port being positioned in throttling relationwith said circumferential groove of said valve member, resilient meansmounted in said housing and positioned to urge said valve member in onedirection for restricting fluid flow from said inlet port to said'second' outlet port while metering said fluid flow from said inlet portto said first outlet port and said valve member being alternatelymovable in the other direction for throttling fluid flow from said inletport to said first outlet port while throttling fluid flow from saidinlet port to said second outlet 'port whereby the fluid flow throughthe first outlet port is maintained at a constant predetermined rateregardless of variation in delivery of fluid to said inlet port by saidsource of fluid delivery.

' '2. An hydraulic circuit comprising a fluid pump'having fluid inletmeans and fluid outlet means, a first pressure conduit communicativelyconnected to the fluid outlet means of said pump, a fluid flow dividingvalve having a fluid inlet 'port and first and second outlet ports, saidfirst pressure conduit being communicatively connected to said inletport of said dividing valve, said' fluid flow dividing valve having ahousing, a reciprocable valve memberjmounte'd within said housing, oneend of saidvalve member being positioned to form a chamber with respectto one end portion of said housing, a bore axially disposed in saidvalve member, a first fluid metering passage disposed in said valvemember communicatively connecting for fluid flow said bore with saidchamher, a circumferential groove disposed on one end portion of saidvalve member, said inlet port being disposed in said housing'andpositioned for continuous registration with said groove, a channeldisposed in said valve member, said channel being positioned tocommunicate for fluid'flow said groove with said chamber, said firstoutlet port being disposed in said housing adjacent the other endportion thereof, a second fluid metering passage disposed at'the otherend of said valve member, said second fluid metering passage beinginregistrable position for communicatively connecting for fluid flow inthrottling relation said'bore with said first outlet port,

second outlet port. being disposed in said housing adjacent saidinletiport and positioned in throttling relation with said groove ofsaid valve member, a captive helical spring mounted intsaid housing andpositioned to urgesaid valvemember in one direction, said valve memberbeing movable in one direction for throttling fluid flow from said inletport to said second outlet port while metering said fluid flow from saidinlet port to said first outlet port and alternately being movable inthe other direction for throttling fluid flow from said inlet port tosaid first outlet port while restricting fluid flow from said inlet portto said second outlet port, a

servo-motor assembly including a servo-motor and an operating valvetherefor or" the kind which by -passes fluid from an inlet port thereofto an outlet port thereof when said servo-motor is at rest, asecondpressure conduit communicatively connecting for fluid flow said firstoutlet port of said fluid flow dividing valve and said inlet portot saidservo-motor assembly, a first discharge conduit communicativelyconnecting said outlet port of said servo-motor assemblyand said fluidinlet means of said fluid pump, a ,relief valve connected to said firstpressure conduit and said first discharge conduit, said relief valvebeing adapted to by-pass fluid under pressure from said first pressureconduit to said first discharge conduit when the fluid pressure in saidfirst pressure conduit exceeds a predetermined value, a second dischargeconduit connected communicatively for fluid flow with saidsecond outletport of saiddividing valve, an hydraulically operable fluid flowregulating valve including an ,hydraulic actuating ram thereforcommunicativelyl connected for fluid flow with said first dischargeconduitand said second discharge conduit, said regulating valve beingadapted to regulate the rate of flow of fluid from said second dischargeconduit to said first discharge conduit, a third dischargeconduitcomrnunicatively connecting for fluid flow said second discharge conduitand said hydraulic ram, an orifice disposed in said third dischargeconduit, said orifice being adapted to reduce theirate of flow of fluidfrom said second discharge conduit to said hydraulic ram, a fourthdischarge conduit communicatively connected for fluid flow with saidthird discharge conduit at a point in said third discharge conduitbetween said hydraulic, ram and said orifice, a first control valvecommunicatively con nected in control relation with said first andfourth discharge conduits, a reversibly operable fluid motor, a firsttube and a second tube cornmunicatively connected to said fluidlmotor,one of said tubes being positioned to conduct fluid under pressure toenergize said fluid motor while the other tube being positioned forconducting the exhaust fluid emanating from said fluid motor, a secondcontrol valve, said second control valve being connectedc'ommunicatively for fluid flow with said first pressure conduit andsaid first discharge conduit and said tubes, said second control valvebeing adapted to connect communicatively for fluid flow one of saidtubes with said first pressure conduit and simultaneously connectingsaid other tube with said first discharge conduit, said hydrauliccircuit being adapted to meter a first portion of said fluid flow fromsaid pump to said servo-motor assembly and the excess of said fluid flowfrom said pump being conducted to the fluid inlet means of said pumpthrough said dividing valve and said regulating valve When said first,and second control valves are in closed position and alternatelyconducting said excess fluid under pressure to said fluid motor whensaid first and second control valves are in open position therebyterminating fluid flow through said regulating valve.

3. An hydraulic circuit comprising a fluid pump having fluid inlet meansand fluid outlet means, a first pressure conduit communicativelyconnected to the fluid outlet means of said pump, a fluid flow dividingvalve having a fluid inlet port and first and second outlet ports, saidfirst pressure conduit beingfcommunicatively connected to said inletport of said dividing Valve, said fluid'flow dividing valve having ahousing, a reciprocable valve member mounted within said housing, a boreaxially end portion of said valvemember, said second fluid meteringpassagebeing iii registrable pennan s cornm'uni'catively connecting forfluid flow in throttling relation said bore with said first outlet port,a snubbing port 'disposed.adjacent said second fiuid iri'eteringpassage, said 7 snubbin g port being positioned for continuouslycommunicating. for fluid flow said bore with said first outlet port,said second outlet port disposed in said housing and being positioned inthrottling relation with said groove of said valve member, resilientmeans mounted in said housing positioned to urge said valve member inone direction for throttling fluid flow from said inlet port to saidsecond outlet port while metering said fluid flow from said inlet portto said first outlet port and alternately being movable in the otherdirection for throttling fluid flow from said inlet port to said firstoutlet port while restricting fluid flow from said inlet port to saidsecond outlet port, a servo-motor assembly in: cluding aservo-rnotor andan operating valve therefor of the kind which by-passes fluid from aninlet port to an outlet port thereof when said servo-motor is at rest, asecond pressure conduit communicatively connecting for fluid flow saidfirst outlet port of said fluid flow dividing valve and said inlet porto f said servo-motor assembly, a first discharge conduit communicativelyconnecting outlet port of said servo-motor assembly and said fluid inletmeans of said fluid pump, a second discharge conduit connec'tedcommunicatively for fluid flow with said second outlet port of saiddividing valve, an hydraulically operable fluid flow regulating valveincluding an hydraulic actuating ram therefore communicatively connectedfor fluid flow with said first discharge conduit andsaid seconddischarge conduit, said regulating valve being adapted to regulate therate of flow of fluid from said second discharge conduit to said firstdischarge conduit, 21 third discharge conduit "communicativelyconnecting for fluid flow said second discharge conduit and saidhydraulic ram, an orifice disposed in said third discharge conduit, saidorifice being adapted to reduce the rate of flow of fluid from saidsecond discharge conduit to said hydraulic ram, a fourth dischargeconduit communicatively connected for fluid flow with said thirddischarge conduit at a point in said third discharge conduit betweensaid hydraulic ram and said orifice, a first control valvecommunicatively connected in control relation with said first and fourthdischarge conduits, a fluid motor, a tube communicatively connected tosaid fluid motor, said tube being positioned to conduct fluid underpressure to energize said fluid motor, a second control valve, saidsecond control valve beingconnected in control relation communicativelyfor fluid flow with said first pressure conduit and said first dischargeconduit and said tube, said second control valve being adapted toconnect communicatively for fluid flow said tube with said firstpressure conduit, said hydraulic circuit being adapted to meter a firstportion of said fluid flow from said pump to said servo-motor assemblyand the excess of said fluid flow from said pump being conducted to thefluid inlet means of said pump through said dividing valve and saidregulating valve when said first and second control valves are in closedposition and alternately conducting said excess fluid under pressure tosaid tube and fluid motor when said first and second control valves arein open positron thereby terminating fluid flow through said regulatingvalve.

4. An hydraulic circuit comprising a fluid pump having fluid inlet meansand fluid outlet means, a first pressure conduit communicativelyconnected to the fluid outlet means of said pump, a fluid flow dividingvalve having a fluid inlet port and first and second outlet ports, saidfirst pressure conduit being communicatively connected to said inletport of said dividing valve, said 'fluid flow dividing valve having ahousing, a reciprocable valve ember mounted within said housing, one endof said valve member being positioned to form a chamber with respect toone end portion of said housing, a bore axially disposed in said valvemember, a first fluid metering passage disposed in said valve membercommunicatively connecting for fluid flow said bore with said chamber, acircumferential groove disposed on one end portion of said valve member,said inlet port being disposed in said housing and positioned forcontinuous registration with said groove, a channel disposed in saidvalve member, said channel being positioned to communicate for fluidflow said groove with said chamber, said first outlet port beingdisposed in said housing adjacent the other end portion thereof,iasecond fluid metering passage disposed at the other end of said valvemember, said second fluid metering passage being in registrable positionfor communicatively connecting for fluid flow in throttling relationsaid bore With said first outlet port, a snubbingport disposed in saidvalve member adjacent said second fluid metering passage, said snubbingport being positioned for continuously communicating for fluid flow saidbore with said first outlet port, said second outlet port being disposedin said housing adjacent saidinlet port and positioned in throttlingrelation with said groove of said valve member, a captive helical springmounted in said housing and positioned to urge said valve member in onedirection, said valve member being movable in one direction forthrottling fluid flow from said inlet port to said second outlet portWhile metering said fluid flow from said inlet port to said first outletport and alternately being movable in the other direction for throttlingfluid flow from said inlet port to said first outlet port whilerestricting fluid flow from said inlet port to said second outlet port,a servo-motor assembly including a servomotor and an operating valvetherefor of the kind which by-passes fluid from an inlet port thereof toan outlet port thereof when said servo-motor is at rest, a secondpressure conduit communicatively connecting for fluid flow said'firstoutlet port of said fluid flow dividing valve and said inlet port ofsaid servo-motor assembly, a first discharge conduit communicativelyconnecting said outlet port of said servo-motor assembly and said fluidinlet means of said fluid pump, a relief valve connected to said firstpressure conduit and said first discharge conduit, said relief valvebeing adapted to by-pass fluid under pressure from said first pressureconduit to said first discharge conduit when the fluid pressure in saidfirst pressure conduit exceeds a predetermined value, a second dischargeconduit connected communicatively for fluid flow with said second outletport of said dividing valve, an hydraulically operable fluid flowregulating valve includ ing an hydraulic actuating ram thereforcommunicatively connected for fluid flow with said first dischargeconduit and said second discharge conduit, said regulating valve beingadapted to regulate the rate of flow of fluid from said second dischargeconduit to said first discharge conduit, a third discharge conduitcommunicatively connecting for fluid flow said second discharge conduitand said hydraulic ram, an orifice disposed in said third dischargeconduit, said orifice being adapted to reduce the rate of flow of fluidfrom said second discharge conduit to said hydraulic ram, a fourthdischarge conduit com municatively connected for fluid flow with saidthird discharge conduit at a point in said third discharge conduitbetween said hydraulic ram and said orifice, a first control valvecommunicatively connected in control relation with said first and fourthdischarge conduits, a reversibly operable fluid motor, a first tube anda second tube cornmunicatively connected to said fluid motor, one 'ofsaid tubes being positioned to conduct fluid under pressure to energizesaid fluid motor while the other tube being positioned for conductingthe exhaust fluid emanating from said fluid motor, a second controlvalve, said sec ond control valve being connected communicatively forfluid flow with said second discharge conduit and said first dischargeconduit and said tubes, said second control valvetbeing adapted toconnect communicatively for fluid flow one of said tubes with saidsecond discharge conduit and simultaneously connecting said other tubewith said first discharge conduit, said hydraulic circuit being adaptedto meter a first portion of said fluid flow from said pump to saidservo-motor assembly and the excess of said fluid flow from said pumpbeing conducted to the fluid inlet means of said pump through saiddividing valve and said regulating valve when said first and secondcontrol valves are in closed position and alternately conducting saidexcess fluid flow to said fluid motor when said first and second controlvalves are in open position thereby terminating fluid flow through saidregulating valve.

'5. An hydraulic circuit comprising a fluid pump having fluid inletmeans and fluid outlet means, a first pressure conduit communicativelyconnected to the fluid outlet means of said pump, a fluid flow dividingvalve having a fluid inlet port and first and second outlet ports, saidfirst pressure conduit being communicatively connected to said inletport of said dividing valve, said fluid flow dividing valve having ahousing, a reciprocable valve member mounted within said housing, a boreaxiallydisposed in said valve member, a circumferential groove disposedon one end portion of said valve member, a first fluid metering passagedisposed in said valve member positioned for communicatively connectingfor fluid flow said bore with said groove, said inlet port beingpositioned in one end portion of said housing for continuousregistration with said groove, said first outlet port disposed in theother end portion of said housing, a second fluid metering passagedisposed at the other end portion of said valve member, said secondfluid metering passage being in registrable position for communicativelyconnecting for fluid flow in throttling relation said bore with saidfirst outlet p0rt, a snubbing port disposed adjacent said second fluidmetering passage, said snubbing port being positioned for continuouslycommunicating for fluid flow said bore with said first outlet port, saidsecond outlet port disposed in said housing and being positioned inthrottling relation with said groove of said valve member, resilientmeans mounted in said housing positioned to urge said valve member inone direction for throttling fluid flow from said inlet port to saidsecond outlet port while metering said fluid flow from said inlet portto said first outlet port and alternately being movable in the otherdirection for throttling fluid flow from said inlet port to said firstoutlet port while restricting fluid flow from said inlet port to saidsecond outlet port, a servo-motor assembly including a servo-motor andan operating valve therefor of the kind which by-passes fluid from aninlet port to an outlet port thereof when said servo-motor is at rest, asecond pressure conduit communicatively connecting for fluid flow saidfirst outlet port of said fluid flow dividing valve and said inlet port'of said servo-motor assembly, a first discharge conduit communicativelyconnecting said outlet port of said servo-motor assembly and said fluidinlet means of said fluid pump, a second discharge conduit connectedcommunicatively for fluid flow with said second outlet port of saiddividing valve, an hydraulically operable fluid flow regulating valveincluding an hydraulic actuating ram therefor communicatively connectedfor fluid flow with said first discharge conduit and said seconddischarge conduit, said regulating valve being adapted to regulate therate of flow of fluid from said second discharge conduit to said firstdischarge conduit, a third discharge conduit communicatively connectingfor fluid flow said second discharge conduit and said hydraulic ram, anorifice disposed in said third discharge conduit, said orifice beingadapted to reduce the rate of flow of fluid from a and said orifice, afirst control valve communicatively connected in control relation withsaid first and fourth dis charge conduits, a fluid motor, a tubecommunicatively connected to said fluid motor, said tube beingpositioned to condut fluid under pressure to energize said fluid motor,a second control valve, said second control valve being connected incontrol relation communicatively for fluid flow with said seconddischarge conduit and said first discharge conduit and said tube, saidsecond control valve being adapted to connect communicatively for fluidflow said tube with said second discharge conduit, said hydrauliccircuit being adapted to meter a first portion of said fluid flow fromsaid pump to said servo-motor assembly and the excess of said fluid flowfrom said pump being conducted to the fluid inlet means of said pumpthrough said dividing valve and said regulating valve when said firstand second control valves are in closed position and alternatelyconducting said excess fluid flow to said tube and fluid motor when saidfirst and second control valves are in open position thereby terminatingfluid flow through said regulating valve.

6. A fluid system for dividing the flow of fluid under limited pressurefrom a source of variable rate fluid delivery having fluid return meanscomprising a servo-motor assembly including a servo-motor and controlmeans therefor, a second fluid motor, said servo-motor assembly being ofthe kind which by-passes fluid from an inlet port thereof to an outletport thereof communicatively connected to said fluid return means whensaid servo-motor is at rest, a fluid flow dividing mechanism having aflow dividing valve communicatively connected to a fluid pressureregulating valve, said fluid flow dividing valve being communicativelyconnected to said source of fluid delivery and said servo-motorassembly, said regulating valve being communicatively connected to saidfluid return means, a first control valve communicatively connected incontrol relation to said regulating valve and said fluid return means, asecond control valve communicatively connectable in control relationwith said second fluid motor and said source of fluid delivery and saidfluid return means, said fluid flow dividing mechanism being adapted tometer a first portion of fluid flow at substantially constant rate fromsaid source of fluid delivery to said servo-motor assembly and divertingthe excess portion of said fluid flow over and above said first portionto said second fluid motor when said first and second control valves arein open position and alternately discharging to said return means saidexcess portion of fluid flow when said first and second control valvesare in closed position.

References Cited in the file of this patent UNITED STATES PATENTS2,363,179 Harrington Nov. 21, 1944 2,603,065 Sarto July 15, 19522,674,092 Gardiner Apr. 6, 1954 2,708,344 Greer May 17, 1955 2,737,196Eames Mar. 6, 1956

